One of the most common metabolic problems among people today is obesity. This condition is due to a greater intake of calories than are expended. Fat is the most concentrated form of energy in the diet with each gram supplying approximately 9 calories. Overall, fat constitutes about 40 percent of the total calories in the diet. If the available calories from fat could be lowered without a decrease in the amount eaten, this would offer a very convenient and practical method by which obesity could be overcome.
Triglycerides are the main component of edible fats and constitute 90 percent of the total amount consumed. One method by which the caloric value of edible fat could be lowered would be to decrease the amount of triglyceride that is absorbed in the body. The usual edible triglyceride fats are almost completely absorbed. The absorbability of triglyceride fats can be decreased by altering the alcohol portion of the molecule. For example, U.S. Pat. No. 3,600,186 describes sugar or sugar alcohol fatty acid esters having at least 4 fatty acid ester groups have been used as non-digestible fats. U.S. Pat. No. 2,962,419 describes non-digestible esters formed by the reaction of a fatty acid with a polyol such as pentaerythritol. U.S. Pat. No. 4,582,715 describes alpha-acylated glycerides as nondigestible fats in low calorie fat-containing food compositions. Patent Cooperation Treaty (PCT) Application No. WO 93/00016 describes a low calorie fat substitute containing a sorbitol fatty acid ester.
Less digestible or absorbed fats have also been made by modification of the fatty acid portion of the ester. For example, U.S. Pat. No. 3,579,548 describes glycerol esters of alphabranched carboxylic acids. J. Food Sci., Vol. 49 (1984), pp. 419-28, in an article by D. Hamm entitled, "Preparation and Evaluation of Trialkoxytricarballyate, Trialkoxycitrate, Trialkoxy-glycerolether, Jojoba Oil and Sucrose Polyester as Low Calorie Replacements of Edible Fats and Oils" describes the use of trialkoxycitrate or trialkoxytricarballyate as low calorie replacements of conventional edible fats and oils.
U.S. Pat. No. 4,959,466 describes partially esterified oligosaccharides and polysaccharides as indigestible fat substitutes. U.S. Pat. Nos. 4,927,658 and 4,927,659 describe trishydroxymethyl ethane and propane esterified with fatty acids or dicarboxylate-extended fatty acid derivatives as partially digestible synthetic fat replacements for foods.
A significant problem in attempting to formulate fat compounds having decreased absorbability and thus low calorie properties is to maintain the desirable and conventional physical properties of edible fat. To be practical, the low calorie fat must resemble conventional triglyceride fat and have the same utility in various fat-containing food compositions such as shortening, margarine and cake mixes. However, the combination of desirable fat-like properties with decreased absorbability or digestibility cannot be predicted with any degree of accuracy.
Food Technology at pg. 314, column 2, describes a process for preparing triglycerides by converting starting material fats to mono- and diglycerides by mixing with glycerol and sodium hydroxide for 0.3 to 3 hours at 200.degree. C. to 250.degree. C. The resulting technical grade mixture is acetylated.
U.S. Pat. No. 2,615,159 describes a process for preparing triglycerides by reacting triacetin with a conventional fat in the presence of a low temperature rearrangement catalyst such as sodium alkoxide suspended in xylene or other low boiling hydrocarbon which is miscible with the fats. The system has two phases.
U.S. Pat. No. 5,434,278 describes a solventless batch process for preparing triglycerides. The process involves interesterifying triglycerides bearing long C.sub.16 to C.sub.22 fatty acid chains with a mixture of triacetin and triglycerides bearing saturated C.sub.3 to C.sub.10 acid residues at a temperature of 100 to 150.degree. C.